Look for the longest chain that contains the maximum possible number of double bonds.
The chain is numbered in such a way that the double bonds end up with the lowest possible numbers, exception made when there is another dominant function in which case the numbering starts by it.
If there are substituents, they are assigned the corresponding numbering in the name.
In the case that two equivalent numberings are possible, one will take the one that assigns the lowest possible numbers to the substituents.
